1. Field of Invention
This invention relates in general to advancing material of continuous length and the guidance of the moving material by means of turn bars in association with other means. More particularly this invention pertains to apparatus and method for continuously advancing a web of material from which envelopes may be fabricated in association with means which permit the angle of entry of the web into an envelope-making machine to be easily adjusted. The apparatus includes turn bar units which guide the web from an initial flat position to an edgewise orientation and then back to the original flat position before entry into an envelope making machine. The second of the turn bar units is attached to a swivel plate. Adjustment of the plate changes the angle at which the flat web enters the envelope machine.
U.S. Pat. No. 3,599,851 is representative of the prior art teaching relative to turn bars, although the teaching is not directed toward the use of turn bars in association with an envelope-making machine.
2. Description of the Prior Art
Machines for rapid manufacture of envelopes from a continuous web are known in the art. One such machine for the making of envelopes from diamond or rhombic shaped blanks is described in U.S. Pat. No. 2,696,255 issued to Heywood. When it is desired to manufacture a different size of envelope, it is necessary to change the angle at which the web enters the cutting means or sheeter knife of the envelope-making machine. This change in web entry angle results in the cutting of a diamond-shaped blank having required size and outline so that when it is folded, it will form the desired new envelope. Previously, it was necessary that the web move in a straight line from the web source to the cutting means of the envelope machine in order to prevent damage to the paper web. Thus, to change the web entry angle to that required, the web supply had to be moved.
As the process associated with this type of envelope-making machine became more elaborate, more equipment was positioned between the web supply and the feed end of the envelope machine where the sheeter knife is located. Thus, for each change in envelope size it became necessary to move the web supply and other equipment located before the sheeter, so that the web could travel in a straight line. In order to eliminate moving each piece of equipment individually, it became the practice to attach all this equipment to the swivel plate of the envelope-making machine. This made it possible to cut blanks of various sizes by moving all of the equipment at the same time.
The above practice of attaching the heavy equipment to the swivel plate of the envelope-making machine also proved unsatisfactory. Any process involved in changing the size of the diamond-shaped envelope blanks was laborious and time consuming, due to the weight and cumbersome nature of the equipment. Accordingly, a long felt need in the art of envelope machine has been apparatus capable of adjusting the angle of the web entry into the cutting means of an envelope-making machine, but which eliminated the necessity to move the heavy equipment used to operate on the web before it entered the feed end of the envelope-making machine. It has also been desired to eliminate the practice of attaching the web source, printer and splicer to the swivel plate of the envelope-making machine. In addition, it is necessary that these problems be remedied without any damage occurring to the paper web.